Annuloplasty Device

ABSTRACT

An annuloplasty device is disclosed comprising first and second support rings having a coiled configuration in which the first and second support rings are arranged as a coil around a central axis, wherein the first and second support rings are configured to be arranged on opposite sides of native heart valve leaflets of a heart valve, a stent arranged around at least a portion of the first and/or second support ring, and wherein the stent comprises retention units. A related method of repairing a defective heart valve is also disclosed.

FIELD OF THE INVENTION

This invention pertains in general to the field of cardiac valve repair.More particularly the invention relates to an annuloplasty device, suchas an annuloplasty ring or helix, for positioning at the heart valveannulus and a method of repairing a defective heart valve.

BACKGROUND OF THE INVENTION

Diseased mitrel and tricuspid valves frequently need replacement orrepair. The mitrel and tricuspid valve leaflets or supporting chordaemay degenerate and weaken or the annulus may dilate leading to valveleak. Mitrel and tricuspid valve replacement and repair are frequentlyperformed with aid of an annuloplasty ring, used to reduce the diameterof the annulus, or modify the geometry of the annulus in any other way,or aid as a generally supporting structure during the valve replacementor repair procedure. The annuloplasty ring is typically implanted aroundthe annulus of the heart valve.

A problem with prior art annuloplasty implants is to achieve correctpositioning at the heart valve and fixate the implant in the correctposition. Suturing devices for annuloplasty implants have disadvantagesthat makes it difficult to suture in the correct position, therebyresulting insufficient suturing strength, and also in a verytime-consuming procedure, which increases the risks for the patient.Furthermore, suturing devices are often not sufficiently compact forcatheter based procedures. The use of clips for positioning annuloplastyimplants is also associated with challenges, in particular whenimplanting helix rings that are to be positioned on either side of aheart valve. Insufficient fixation of such implant lead to traumaticeffects since the fixation structure must ensure the correct position ofthe device over time. A further problem in the prior art is thus also toachieve a reliable fixation at the annulus of the heart valve. Anannuloplasty implant is intended to function for years and years, so itis critical with long term stability in this regard.

The above problems may have dire consequences for the patient and thehealth care system. Patient risk is increased.

Hence, an improved annuloplasty implant or device would be advantageousand in particular allowing for avoiding more of the above mentionedproblems and compromises, and in particular ensuring secure fixation ofthe annuloplasty device, during the implantation phase, and forlong-term functioning, in addition to a less complex procedure, andincreased patient safety. A related method would also be advantageous.

SUMMARY OF THE INVENTION

Accordingly, examples of the present invention preferably seek tomitigate, alleviate or eliminate one or more deficiencies, disadvantagesor issues in the art, such as the above-identified, singly or in anycombination by providing a device according to the appended patentclaims.

According to a first aspect an annuloplasty device is providedcomprising first and second support rings having a coiled configurationin which the first and second support rings are arranged as a coilaround a central axis, wherein the first and second support rings areconfigured to be arranged on opposite sides of native heart valveleaflets of a heart valve, a stent arranged around at least a portion ofthe first and/or second support ring, and wherein the stent comprisesretention units.

According to a second aspect a method of repairing a defective heartvalve is provided. The method comprises positioning a first support ringof an annuloplasty device on a ventricular side of the heart valve,positioning a second support ring of the annuloplasty device on anatrial side of the heart valve, whereby the first and second supportrings are arranged as a coil extending through a commissure of the heartvalve, the first and/or second support ring comprising a stent arrangedaround at least a portion of the first and/or second support ring, thestent comprising retention units, and positioning the stent in abutmentwith valve tissue along said portion so that the retention units areengaged into tissue of the heart valve.

Further examples of the invention are defined in the dependent claims,wherein features for the first aspect may be implemented for the secondaspect and vice versa.

Some examples of the disclosure provide for a facilitated positioning ofan annuloplasty device at a heart valve.

Some examples of the disclosure provide for a facilitated fixation of anannuloplasty device at a heart valve.

Some examples of the disclosure provide for a less time-consumingfixation of an annuloplasty to a target site.

Some examples of the disclosure provide for securing long-termfunctioning and position of an annuloplasty device.

Some examples of the disclosure provide for a reduced risk of damagingthe anatomy of the heart such as the annulus or the valve leaflets.

Some examples of the disclosure provide for a more secure implantationof an annuloplasty device in narrow anatomies.

It should be emphasized that the term “comprises/comprising” when usedin this specification is taken to specify the presence of statedfeatures, integers, steps or components but does not preclude thepresence or addition of one or more other features, integers, steps,components or groups thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects, features and advantages of which embodiments ofthe invention are capable of will be apparent and elucidated from thefollowing description of embodiments of the present invention, referencebeing made to the accompanying drawings, in which

FIG. 1 is a schematic illustration of an annuloplasty device, in aperspective view, where stents are arranged around at least a portion ofthe first and second support rings, according to an example of thedisclosure;

FIG. 2 is a schematic illustration of a stent of the annuloplastydevice, where the stent has a plurality of retention units, according toan example of the disclosure;

FIG. 3 is a schematic illustration of a portion of a stent of theannuloplasty device, in a further detailed view, according to an exampleof the disclosure;

FIG. 4 a is a schematic illustration of a portion of a stent of theannuloplasty device, in detailed view, where a retention unit thereof isin a retracted state, according to an example of the disclosure;

FIG. 4 b is a schematic illustration of a portion of a stent of theannuloplasty device, in detailed view, where a retention unit thereof isin an expanded state, according to an example of the disclosure;

FIG. 4 c is a schematic illustration of a portion of a stent of theannuloplasty device, in front view of the retention unit thereof, wherethe retention unit is in a retracted state, according to an example ofthe disclosure;

FIG. 4 d is a schematic illustration of a portion of a stent of theannuloplasty device, in detailed view, where a retention unit thereof isin a retracted state, according to an example of the disclosure;

FIG. 4 e is a schematic illustration of a portion of a stent of theannuloplasty device, in detailed view, where a retention unit thereof isin an expanded state, according to an example of the disclosure;

FIGS. 5 a-b are schematic illustrations of the annuloplasty device, incross-sectional views, where a retention unit of a stent is in anexpanded state, according to examples of the disclosure;

FIG. 6 is a schematic illustration of the annuloplasty device, inside-view, where first and second support rings are separated by atransition region, according to examples of the disclosure;

FIG. 7 a is a schematic illustration of an annuloplasty device, in aside view, where the annuloplasty device is positioned above and belowvalve leaflets, according to an example of the disclosure;

FIG. 7 b is a schematic illustration of an annuloplasty device, in atop-down view, according to an example of the disclosure;

FIGS. 8 a-b are schematic illustration of a stent of the annuloplastydevice, where the stent is radially expanded (a) and radially retracted(b), respectively, according to an example of the disclosure;

FIGS. 9 a-b are schematic illustration of a stent of the annuloplastydevice, where the stent is radially expanded (a) and radially retracted(b), respectively, according to an example of the disclosure;

FIGS. 10 a-d are schematic illustrations of a stent of the annuloplastydevice, where the stent has a plurality of retention units, according toexamples of the disclosure;

FIG. 11 a is a flow chart of a method of repairing a defective heartvalve, according to an example of the disclosure; and

FIG. 11 b is another flow chart of a method of repairing a defectiveheart valve, according to an example of the disclosure.

DESCRIPTION OF EMBODIMENTS

Specific embodiments of the invention will now be described withreference to the accompanying drawings. This invention may, however, beembodied in many different forms and should not be construed as limitedto the embodiments set forth herein; rather, these embodiments areprovided so that this disclosure will be thorough and complete, and willfully convey the scope of the invention to those skilled in the art. Theterminology used in the detailed description of the embodimentsillustrated in the accompanying drawings is not intended to be limitingof the invention. In the drawings, like numbers refer to like elements.

The following description focuses on an embodiment of the presentinvention applicable to cardiac valve implants such as annuloplastyrings. However, it will be appreciated that the invention is not limitedto this application but may be applied to many other annuloplastyimplants and cardiac valve implants including for example replacementvalves, and other medical implantable devices.

FIG. 1 schematically illustrates an example of an annuloplasty device100 comprising a first support ring 101 and second support ring 102which are adapted to be arranged as a coil, i.e. in a helix-shape, in acoiled configuration around a central axis 103, as illustrated in FIG. 1. The device 100 is arranged in the coiled configuration at least whenin a relaxed state of the material from which the device 100 is formed,i.e. free from outside forces acting upon the device 100. Thecoil-shaped device 100 has two free ends 116, 116′. The first and secondsupport rings 101, 102, and the respective free ends 116, 116′, areconfigured to be arranged on opposite sides of native heart valveleaflets 301 of a heart valve, as illustrated in the side view of FIG. 7a . As shown in FIG. 7 a , the first support ring 101 may be arranged onan atrial side of the heart valve, and the second support ring 102 maybe arranged on a ventricular side (the second support ring 102 is alsoshown with dashed lines in the top-down view of FIG. 7 b , where thevalve leaflets have been omitted). The second support ring 102 isillustrated with a dashed line and is in these examples arranged on theventricular side of the heart valve, whereas the first support ring 101is arranged on the atrial side of the heart valve (shown with solid linein FIG. 7 b ). The first support ring 101 may thus extend along theannulus of the heart valve on the atrial side. The first and secondsupport rings 101, 102, are connected to form a coil- or helix shapedring, as an integral continuous ring. The coil extends through the valveopening at a commissure 302, 302′, thereof. In the example of FIG. 7 b ,the coil extends through commissure denoted as 302′, but is should beunderstood that the annuloplasty device 100 may extend through thecommissure denoted as 302 in other examples. The first and secondsupport rings 101, 102, may thus assume the coiled configuration alsowhen in an implanted state. As explained further below, the device 100may comprise a shape-memory material, so that the device 100 re-assumesthe coiled configuration after having been delivered from a catheter(not shown) to the target site, after having been temporarily restrainedin an elongated configuration of the catheter. The annuloplasty device100, i.e. annuloplasty implant 100, may comprise a shape memorymaterial, such as NiTiNol, or another suitable biocompatible alloy thatcan be heat-set in defined shapes, i.e. in a defined relaxed shape inabsence of outside acting forces, in a heat treatment procedure. Theannuloplasty device 100 may pinch the tissue of the valve leaflets 301,between the first and second support rings 101, 102, i.e. with forcesacting in parallel with the central axis 103.

The annuloplasty device 100 further comprises a stent 105, 105 a, 105 b,105 c, arranged around at least a portion of the first and/or secondsupport ring 101, 102. FIG. 1 shows an example where three stents 105 a,105 b, 105 c, are arranged around portions of the first and secondsupport rings 101, 102. FIGS. 2-4 are further detailed views of a stent105 configured to be arranged around at least a portion of the firstand/or second support ring 101, 102. It should be understood that theannuloplasty device 100 may comprise a varying number of stents 105depending on the particular implant site of the annuloplasty device 100.Furthermore, the ratio of the total length of the first and/or secondsupport ring 101, 102, covered by the stent 105, 105 a, 105 b, 105 c,may vary depending on the placement of the annuloplasty device 100.Although reference is made to stent 105 in the present disclosure, itshould be understood that any of the stents 105 a, 105 b, 105 c, asexemplified in FIG. 1 may comprise the features as described for stent105 in relation to FIGS. 2-10 . The lattice or framework of the stent105 may be formed by laser cutting of a tube-shaped material, such asNiTinol or other bio compatible metal alloy and then pushed over thefirst and/or second support rings 101, 102. The stent 105 thus has ahollow interior to accommodate the first and/or second support rings101, 102. The stent comprises retention units 104, 104′, asschematically illustrated in FIG. 1 and in the detailed views of FIGS.3-5, 10 . The retention units 104, 104′, are shaped to pierce intotissue at the heart valve. The retention units 104, 104′, are fixed inrelation to the stent 105, and the stent 105 is fixed in relation to thefirst and/or second support ring 101, 102, on which the stent 105 isarranged. Thus, having stents 105 a, 105 b, 105 c, arranged around atleast part of the first and/or second support rings 101, 102, providesfor anchoring the annuloplasty device 100 to the valve tissue with theretention units 104, 104′. The first and/or second support rings 101,102, are thus provided with a robust anchoring mechanism by utilizing astent 105, 105 a, 105 b, 105 c, as an intermediate fixation structurefor the retention units 104, 104′, thereby dispensing with the need toattach any retention structures directly to the first and/or secondsupport rings 101, 102. The stent 105 thus provides for increasing thereliability of the anchoring mechanism of the annuloplasty device 100 asthe number of separate structures needing to be joined together can bereduced, in particular in the example where the retention units 104,104′, are integrated with the stent 105 as mentioned below. Long-termreliability of the annuloplasty device 100 may thus be improved. Themanufacturing of the annuloplasty device 100 may thus also befacilitated, as the number of separate elements is minimized.Manufacturing tolerances may thus be easier to comply with and theoverall complexity and associated costs may be reduced, providing for amore viable annuloplasty implant 100. Having an annuloplasty device 100with stents 105, 105 a, 105 b, 105 c, and associated retention units104, 104′, also provides for a modular annuloplasty device 100 where acore structure of the first and second support rings 101, 102, may beprovided with a stents 105, 105 a, 105 b, 105 c, having retention units104, 104′, in varying configurations and shapes depending on theparticular application. The annuloplasty device 100 may thus be tailoredto the particular patient and anatomical circumstances more easily andpatient safety can be further improved.

As elucidated above, the retention units 104, 104′, may be formed fromthe material of the stent 105. The retention units 104, 104′, may thusbe integrated with the stent 105. The detailed view of FIG. 4 c is aschematic example of how retention unit 104 is formed as a part of theframework of the stent 105. The retention unit 104 may thus be cut as anelongated structure with a free tip 107 within the structural frameworkof the stent 105. In the example of FIG. 4 c , the retention unit 104 issurrounded by support elements 108 of the stent 105. The examples inFIGS. 2-4 show support elements 108 arranged in a rhombic pattern orclosed cells 122, where the retention units 104 extend into the void ofindividual rhombs or cells 122 at defined positions along the length ofthe stent 105. The stent 105 may thus comprise a plurality of supportelements 108 forming a stent framework of closed cells 122, as furtherschematically illustrated in the examples shown in FIGS. 4 d-e . A firstsupport element 108 a of the plurality of support elements 108 of a cell122 may be movable as a retention unit 104, 104′, along a radialdirection (R), perpendicular to a longitudinal direction (L) of thestent 105, as schematically illustrated in FIGS. 4 d-e . The retentionunit 104 illustrated in FIGS. 4 d-e may thus be part of the supportelements 108 forming a closed cell 122. FIGS. 4 d-e show the retentionunit 104, i.e. the first support element 108 a, arranged in a retractedstate (p₁) (FIG. 4 d ), and expanded state (p₂) (FIG. 4 e ),respectively. The retention unit 104, or first support element 108 a,may be expanded like a bow-like structure in the radial direction (R) inthe expanded state (p₂). The bow-like shape of the first support element108 a may thus be configured to apply a pressure into the valve tissueand increase the retention force of the stent 105 at the annulus. Theretention unit 104, or first support element 108 a, may be folded intoan undulated or otherwise curved or folded shape in the retracted state(p₁), as exemplified in FIG. 4 d.

It should be understood the support elements 108 may be cut to formvarying patterns. Forming the retention units 104, 104′, as integratedstructures of the framework of the stent 105 provides for robust andstrong retention units 104, 104′, and a minimized risk of dislocationsor deformations thereof over time. An overall robust and reliablefixation mechanism of the annuloplasty device 100 is thus provided.Manufacturing is also facilitated, as mentioned above, as the number ofseparate elements of the annuloplasty device 100 requiring assembly isminimized. The retention units 104, 104′, may be cut to form variousshapes for optimizing the gripping force into the tissue. The retentionunits 104, 104′, may be formed by different cutting techniques such asby laser cutting techniques.

The retention units 104, 104′, may be heat-set to assume a defined bentshape as schematically illustrated in the example of FIG. 4 b or 4 e,showing an expanded state (p₂) of the retention unit 104. The expandedstate (p₂) may thus correspond to a relaxed state of the retention unit104 where the latter is not acted upon by external forces. The retentionunit 104 may be bent and heat-treated during manufacturing so that theretention unit 104 assumes a defined shape in the expanded state (p₂).The retention unit 104 may thus have a bias towards the expanded state(p₂), by striving towards the relaxed expanded state (p₂).

The retention units 104, 104′, may thus be resiliently moveable from aretracted state (p₁) to the expanded state (p₂). For example, a forcemay be applied to the retention unit 104 so that it bends and assumes aretracted position or state (p₁), as exemplified in FIG. 4 a , e.g. if adelivery catheter (not shown) applies a compressive force onto the stent105 and the related retention unit 104. As the stent 105 is ejected fromthe delivery catheter, when the annuloplasty device 100 is deployed fromthe delivery catheter, the compressive force is removed and theresilience of the retention unit 104 cause it to move towards theexpanded state (p₂). This provides for an effective deployment of theretention units 104, 104′, as the first and second support rings 101,102, of the annuloplasty device 100 are ejected from the deliverycatheter. The retention units 104, 104′, can thus expand and pierce intothe valve tissue. The cross-section of the annuloplasty device 100 maybe minimized as the retention units 104, 104′, may assume the retractedstate (p₁) when positioned inside the delivery catheter. A smallercross-section provides for a facilitated navigation of the annuloplastydevice 100 to a target site in the heart. The delivery catheter may alsobe subject to less abrasion and wear from the retention units 104, 104′,as these may assume the retracted state (p₁) inside the deliverycatheter, causing less friction between the tip 107 and the inside lumenof the delivery catheter. Reduced friction also facilitates moving theannuloplasty device 100 along the delivery catheter, requiring lessforce and improving the amount of control.

Hence, the retention units 104, 104′, may be flexible to bend from theexpanded state (p₂) to the retracted state (p₁). This allows also forthe retention units 104, 104′, to flex to the retracted state (p₁) ifwithdrawing the annuloplasty device 100 into a delivery catheter, incase the implantation is aborted or repositioning is needed. Theannuloplasty device 100 may thus re-assume the compact cross-sectionalprofile.

In one example the retention units 104, 104′, may comprise ashape-memory material, where activation of the shape-memory materialcauses the retention units 104, 104′, to transfer from the retractedstate (p₁) to the expanded state (p₂). For example, the shape-memorymaterial may be temperature activated, so that the retention units 104,104′, move towards the expanded state (p₂) when subject to heating tothe body temperature. This provides for an advantageous deployment ofthe retention units 104, 104′, in some applications.

The retention units 104, 104′, may be aligned essentially flush with anouter diameter (D) of the stent 105 in the retracted state (p₁), asschematically illustrated in FIG. 4 a or 4 d. This provides for acompact cross-sectional profile of the annuloplasty device 100 as wellas reduced risk of high pressure and abrasion of the retention units104, 104′, against an inner lumen of a delivery catheter.

The stent 105 may be radially contractible along a radial direction (R),perpendicular to a longitudinal direction (L) of the stent 105, so thatthe stent 105 exerts a force (F) on the first and/or second support ring101, 102. The radial (R) and longitudinal direction (L) of the stent 105is schematically indicated in FIG. 3 . The examples illustrated in FIGS.5 a-b are cross-sectional views of the annuloplasty device 100,illustrating the stent 105 arranged around the first- or second supportring 101, 102, and a retention unit 104 in the expanded state (p₂). Thestent 105 may thus be radially contractible towards the first and/orsecond support ring 101, 102, thereby exerting a force (F) onto thelatter as indicated with arrows F in the illustrations of FIGS. 5 a-b .The stent 105 may thus assume a fixed position in relation to the firstand/or second support ring 101, 102, as the force (F) creates frictionbetween the stent 105 and the first and/or second support ring 101, 102.The framework of the stent 105 may thus be cut to allow movement in theradial direction (R), i.e. allowing the support elements 108 of theframework to move in relation to each other, so that the diameter (D) ofthe stent 105 is variable, as further described with reference to FIGS.8 a-b and 9 a-b . The stent 105 may be resiliently expandable in theradial direction (R) so that the stent 105 may be expanded to a radiallystretched state. The stent 105 may then strive towards a contractedrelaxed state with an inner diameter being less than the inner diameterin the radially stretched state. The inner diameter in the radiallystretched state may be denoted ds (see e.g. FIG. 5 a-b ) and may be moreor equal to an outer diameter (d r) of first and/or second support ring101, 102. The stent 105 may thus be positioned over the first and/orsecond support ring 101, 102, when in the radially stretched state. Thestent 105 will thus strive towards the contracted relaxed state with areduced inner diameter, and accordingly exert the aforementioned force(F) on the first and/or second support ring 101, 102. This provides fora facilitated fixation of the position of the stent 105 in relation tothe first and/or second support ring 101, 102. The example in FIG. 5 ashows a cover 106 between the stent 105 and the first and/or secondsupport ring 101, 102, as described in more detail below. The differencebetween dr and ds is thus larger in this case.

The stent 105 may comprise a shape-memory material in one example.Activation of the shape-memory material may cause the stent 105 tocontract to a reduced diameter, along the radial direction R, to apply aforce (F) on the first and/or second support ring 101, 102. For example,the shape-memory material may be temperature activated, so that thestent 105 strives towards a reduced inner diameter when subject toheating to the body temperature. This provides for increasing the force(F) exerted on the first and/or second support ring 101, 102, to attaina secure fixation of the stent 105 thereto.

FIGS. 8 a-b and 9 a-b show examples of a radially contractible andexpandable stent 105. The stent 105 may comprise support elements 108configured to be contractible and expandable so that an outer diameter(D₁, D₂) of the stent 105 is variable between an expanded diameter (D₁)and a contracted diameter (D₂) while a predefined length (L₁) of thestent 105 is essentially maintained. Thus, as the support elements 108undergo a movement and the diameter varies between D₁ and D₂, theoverall length (L₁) of the stent 105 may be fixed. FIGS. 8 a-b and 9 a-bshow a length L₁ of a section of the stent 105 but it should beunderstood that this may correspond to the overall or total length ofthe stent 105 in the longitudinal direction (L). The stent 105 thusexhibit limited or no contraction in the longitudinal direction (L) asthe diameter (D₁, D₂) varies. The stent 105 may be expanded to D₁ andpositioned on the first and/or second support ring 101, 102, andsubsequently retracted to D₂ to apply a force radially inwards andthereby fix its position on the first and/or second support ring 101,102, while undergoing no or insignificant variations in the length (L₁)of the stent 105. This provides for a facilitated and more accuratepositioning of the stent 105 on the first and/or second support ring101, 102. The tailoring of the stent 105 to first and second supportrings 101, 102, of different dimensions is thus facilitated as theposition and coverage of the stent 105 over the first and/or secondsupport ring 101, 102, can be predicted with improved accuracy.

The support elements 108 may have different shapes configured topredominantly allow movement of the overall framework of the stent 105in the radial direction (R), with limited or no movement in thelongitudinal direction (L). FIGS. 8 a-b show an example where thesupport elements 108 are curved in S-shapes. The S-shaped supportelements 108 are stretched when applying a force in the radial direction(R) so that the stent 105 assumes the expanded diameter (D₁) in FIG. 8 a. As the external force is released, the S-shaped support elements 108may contract again so that the stent 105 may assume the contracteddiameter (D₂) in FIG. 8 b . The length L₁ of the stent 105 is notchanged. It should be understood that some movement may occur that couldhave minor affect on the length (L₁) of the stent 105, but that themovement in the radial direction (R) is significantly larger than themovement in the longitudinal direction (L). The ratio between themovement in the radial direction (R) and the movement in thelongitudinal direction (L) may for example be in the range 5:1 to 10:1for a particularly advantageous and improved fixation of the stent 105on the first and/or second support ring 101, 102. It is conceivable thatthe support elements 108 may be curved in different shapes to allow theradial movement as described, such as C-shapes or Z-shapes.

FIGS. 9 a-b show an example where the support elements 108 are curved inbow-shapes. The bow-shaped support elements 108, or the S-shaped supportelements 108, may be arranged to form an essentially cylindrical shapeof the stent 105. The support elements 108 may thus extend generallyacross a surface of such cylindrical shape. The bow-shaped supportelements 108 may be stretched when applying a force in the radialdirection (R) so that the stent 105 may assume the expanded diameter(D₁) in FIG. 9 a . As the external force is released, the bow-shapedsupport elements 108 may contract again so that the stent 105 may assumethe contracted diameter (D₂) in FIG. 9 b . As described above, there isno or insignificant movement of the stent 105 in the longitudinaldirection (L) compared to the movement in the radial direction (R).

As exemplified in FIGS. 8 a-b and 9 a-b , the support elements 108 maycomprise an elongated main frame 121 extending essentially along thelongitudinal direction (L) of the stent 105. The elongated main frame121 may define the aforementioned predefined length (L₁) of the stent105. The elongated main frame 121 may thus have an essentially fixedposition in the longitudinal direction (L) when the outer diameter ofthe stent 105 varies between the expanded diameter (D₁) and thecontracted diameter (D₂). This provides for effectively controlling thelength of the stent 105 in the longitudinal direction (L).

FIGS. 10 a-d show examples of the stent 105 having different supportelements 108 and retention units 104. FIGS. 10 a-b show an example wherethe support elements 108 are S-shaped. The retention units 104 may beshaped as expandable bows, as described above, and schematicallyillustrated in FIG. 10 a . A retracted state (p₁) is shown, as well asan expanded state (p₂) where the bows are illustrated with dashed lines.The retention unit 104 may be part of the support elements 108 asdescribed in relation to FIGS. 4 d-e . As mentioned, the supportelements 108 may comprise an elongated main frame 121. In the lattercase, the retention unit 104 may be part of the elongated main frame121. FIG. 10 b show an example where the retention units 104 may beshaped as expandable prongs or hook-like structures. A retracted state(p₁) is shown, as well as an expanded state (p₂) where the prongs orhook-like structures are illustrated with dashed lines. FIGS. 10 c-dillustrate further examples where the bow-like (FIG. 10 c ) or hook-like(FIG. 10 d ) retention units 104 are arranged on bow-like supportelements 108 of a stent 105. A retracted state (p₁) is shown, as well asan expanded state (p₂). The retention units 104 may be movable betweenthe retracted state (p₁) and the expanded state (p₂) when the stent 105has the contracted outer diameter (D₂), e.g. when fixed to the firstand/or second support ring 101, 102, in order to anchor the stent 105into the valve tissue.

The annuloplasty device 100 may comprise a cover 106 arranged around atleast a portion of the first and/or second support ring 101, 102. Thecover 106 may be configured to promote endothelialization and theingrowth of cells over the annuloplasty device 100. For example, thecover 106 may have a surface which is more porous than the surface ofthe first- and second support rings 101, 102, which promotes the growthof cells over the annuloplasty device 100. The cover 106 may comprise aweave of a textile or a polymer. The stent 105 may be arranged around atleast a portion of the cover 106. The cover 106 may be arranged aroundthe entire length of the first- and second support rings 101, 102.

The stent 105 may exert a force onto the cover 106 so that the cover 106is pinched between the stent 105 and the first and/or second supportring 101, 102, as exemplified in the schematic illustration of FIG. 5 a. Having a cover 106 pinched between the stent 105 and the first and/orsecond support ring 101, 102, provides for attaining a secure fixationof the position of the cover 106 and the stent 105 relative the firstand/or second support ring 101, 102. The stent 105 may thus strivetowards an inner diameter which is smaller than an outer diameter of thecover 106 when the latter is arranged around the first and/or secondsupport ring 101, 102, so that a force (F) is exerted radially inwardsand pinches the cover 106 against the outer surface of the first and/orsecond support ring 101, 102. In case the stent 105 is formed from atemperature activated shape-memory material, the stent 105 may increasethe force (F) radially inwards as the stent 105 is heated to the bodytemperature, which further increases the strength of the fixation of thestent 105 relative the first and/or second support ring 101, 102.

The first support ring 101 may comprise a first posterior bow 113 and afirst anterior portion 114. The second support ring 101 may comprise asecond posterior bow 113′ and a second anterior portion 114′. The firstand second posterior bows 113, 113′, may be adapted to conform to aposterior aspect of the heart valve, i.e. along the posterior leaflet,having a bow-shaped extension. The first and second anterior portions114, 114′, may each have a straighter extension or at least an extensionwhich is less bent than the bow-shaped posterior sides 113, 113′. Thisis exemplified in FIG. 7 b . The first and second anterior portions 114,114′, may thus be adapted to conform to an anterior aspect of the heartvalve, i.e. along an anterior leaflet. As mentioned, the first supportring 101 may be adapted to be arranged on an atrial side of the heartvalve, and the second support ring 102 may be adapted to be arranged ona ventricular side of the heart valve, as exemplified in FIG. 7 a . FIG.7 b show schematic top-down view where the second ring 102 is shown withdashed lines and the first ring 101 is shown with a solid line. Thetransition point between the first and second rings 101, 102, is in theexample of FIG. 7 b at the commissure denoted 302′.

The first anterior portion 114 may comprises an anterior stent 105 c.The anterior stent 105 c comprises a plurality of retention units 104extending towards the second support ring 102 in their expanded state(p₂), as schematically illustrated in FIG. 1 . The second anteriorportion 114′ may comprise a smooth surface free from retention units104, as further shown in the example of FIG. 1 . This provides for asecure anchoring into the tissue with the first anterior portion 114 atthe atrial side, while at the same time the risk of tissue damage isminimized in the ventricle along the second anterior portion 114′.

The first posterior bow 113 may comprise a first posterior stent 105 a.The first posterior stent 105 a may comprise a first plurality ofretention units 104 extending towards the second support ring 102 intheir expanded state (p₂), as schematically illustrated in FIG. 1 . Thesecond posterior bow 113′ may comprise a second posterior stent 105 b.The second posterior stent 105 b may comprise a second plurality ofretention units 104′ extending in a direction towards the firstplurality of retention units 104. The first and second pluralities ofretention units 104, 104′, may thus extend in opposite directions alongthe axial direction 103. Having retention units 104, 104′, at both sidesalong the first and second posterior bows 113, 113′, provides forincreasing the retention force and the strength by which theannuloplasty device 100 is fixated at the valve. The retention units104, 104′, engage the tissue from both sides of the heart valve,creating a strong retention force in the radial direction, i.e.perpendicular to the axial direction 103. The first and second supports101, 102, pinch the tissue from both sides of the valve, so that theretention units 104, 104′, a forced into the tissue. The retention units104, 104′, provides for shaping the annulus as desired even with areduced pinching force, since the retention units 104, 104′, providesfor fixating the shape of the annulus in the radial direction because ofthe mentioned retention force. This provides for a more reliableimplantation at the heart valve, both in the short term and in the longterm.

Each individual retention unit 104, 104′, may engage or pierce into thetissue with a short distance, for a minimum amount of injury to thetissue. The sum of the retention force and friction created from all theretention units 104, 104′, still provides for a strong fixation into thetissue. The scar healing will be quick since each individual retentionunit 104, 104′, as relatively small dimensions. This provides for anon-traumatic and still secure fixation of the annuloplasty device 100.Hence, the retention units 104, 104′, may provide for tissue fixation atmultiple points across the annuloplasty device 100 resulting in reducedforces per fixation point, and no need for bulky stitching device orknotting device. There is further no risk of coronary artery occlusionor coronary sinus perforation. Hence, the annuloplasty device 100provides for ease of operation, and a less time consuming procedure thanstitching.

Having a plurality of separate stents 105 a, 105 b, 105 c, arrangedalong the posterior bows 113, 113′, and the first anterior portion 114allows further for having the stents 105 a, 105 b, 105 c, displaced fromintermediate portions 109 extending therebetween. The intermediateportions 109 as indicated in FIG. 1 have a greater radius of curvaturethan the posterior bows 113, 113′, and the anterior portions 114, 114′.Having stents 105 a, 105 b, 105 c, arranged at a distance from theintermediate portions 109 provides for maintaining a greater flexibilityof the first and second support rings 101, 102, along the intermediateportions 109, and a facilitated bending along the latter.

The retention units 104, 104′, may be evenly spaced along the stents105, 105 a, 105 b, 105 c, as exemplified in FIG. 1 and FIG. 2 . Sucheven distribution of the fixation points provides for a reliableanchoring to the tissue, minimizing the risk of localized pressurepeaks. It should be understood however that the distance between each ofthe retention units 104, 104′, may be varied to optimize the anchoringannuloplasty device 100 to different anatomies. The first and/or secondanterior portion 114, 114′, may have 5 to 6 retention units 104, 104′,respectively. The first and/or second posterior portion 113, 113′, mayhave 6 to 8 retention units 104, 104′, respectively. This may providefor a particularly efficient fixation to the tissue while minimizing theoverall tissue penetration. It should be understood however that thenumber of retention units 104, 104′, may be varied to optimize theanchoring annuloplasty device 100 to different anatomies and valves ofdifferent size. In one example the length of the retention units 104,104′, is in the range 0.5-1.5 mm. In another example the length of theretention units 104, 104′, is in the range 0.8-1.2 mm, such as 1.0 mm,which may provide for a particularly advantageous fixation into thetissue while being easy to deploy via a delivery catheter.

The first support ring 101 may transition to the second support ring 102over a transition section 120, as illustrated in FIG. 6 . The stent 105has been omitted from FIG. 6 for a clearer illustration. The transitionsection 120 is adapted to be arranged at a commissure 302, 302′, of theheart valve leaflets, e.g. at a commissure 302′ as illustrated in FIG. 7b . The first and second support rings 101, 102, extend in respectivefirst and second coil planes 101′, 102′, being essentially perpendicularto the central axis 103. The transition region 120 may bend at leastpartly along the central axis 103 so that the first coil plane 101′ isseparated a distance (d₁) from the second coil plane 102′ along thecentral axis 102 (i.e. along a direction parallel to the central axis)at the transition region 120. Having such transition section 120 wherethe coil planes 101′, 102′, are locally displaced a distance (d₁), andat a position corresponding to the location of the commissure 302, 302′,provides for improved accommodation of the first and second supportrings 101, 102, to the anatomy at the opposite sides of the valve, inparticular as the heart beats. This allows for the retention units 104,104′, of the stent 105, 105 a, 105 b, 105 c, to effectively pierce intothe tissue as the first and second support rings 101, 102, accommodateto the anatomy.

Further, having a step-down in the coil planes 101′, 102′, or an“S-shape”, or “Z-shape”, at the transition region 120 due to separationdistance (d₁) provides for a better coaptation of the first and secondsupport rings 101, 102, at the commissure 302, 302′. I.e. the risk ofhaving the moving valve leaflets pulling on any of the support rings101, 102, at the commissure 302, 302′, is minimized because the firstcoil plane 101′ of the first support ring 101 on the atrial sidetransitions to the second coil plane 102′ of the second support ring 102in a shorter distance at the transition region 120 due to thedisplacement (d₁). This means that the first and second support rings101, 102, may conform better to the two opposite sides of the valveclose to the commissure 302, 302′. The annuloplasty device 100 may thusbe secured at the valve in a safer manner, while the risk ofdislocations is minimized. The position of the transition section 120may be varied depending on which commissure 302, 302′, the first/secondsupport rings 101, 102, extend through the valve leaflets. Thetransition section 120 may thus have an increased slope or pitchrelative the central axis 103 compared to the remaining portions of thefirst and second support rings 101, 102.

The transition section 120 may bend at least partly along a radialdirection (r) of the coiled configuration of the first and secondsupport rings 101, 102, where the radial direction (r) is perpendicularto the central axis 103, so that the transition section 120 is concavetowards the radial direction (r). Such concave bend, or “C-curve”, ofthe transition section 120 towards the radial direction (R) provides forfurther improving the coaptation of the first and second support rings101, 102, to the valve anatomy close to the commissure 302, 302′. Therisk of having a disadvantageous force transfer or friction between themoving valve leaflets and any of the support rings 101, 102, at thecommissure 302, 302′, is minimized. The first and second support rings101, 102, may extend along the annulus as far as possible whileextending through the commissure 302, 302′, with minimized impact on thevalve motion, as the concave bend of the transition section 120 allowsfor adapting to anatomies where the commissure 302, 302′, is locatedloser to the central axis 103 than the annulus. The annuloplasty device100 may thus be secured at the valve in a further improved manner, whilethe risk of dislocations in the long term is minimized.

The first and second support rings 101, 102, may have respective freeends 116, 116′, as illustrated in FIG. 1 . The free ends 116, 116′, maybe configured to be arranged on opposite sides of the native heart valveleaflets. The two free ends 116, 116′, may be displaced from each otherwith a peripheral off-set distance extending in a coil plane. The coilplane is substantially parallel to an annular periphery of the coilformed by the first and second support rings 101, 102, and perpendicularto the axial direction 103. The coil plane accordingly corresponds tothe plane spanned by the annular periphery of the device 100 when in thecoiled configuration. The peripheral off-set distance between the twofree ends 116, 116′, thus extends substantially perpendicular to thecentral axis 103. This means that, when the device 100 is positioned inthe implanted state, around the annulus of the heart valve, the two freeends 116, 116′, will be separated along the plane of the valve. Havingsuch off-set 117 in the plane of the valve, resulting in a reducedlength of the first or second support rings 101, 102, may beadvantageous in some anatomies where there might be a risk ofinterference of the first or second support rings 101, 102, with thevalve motion.

A method 200 of repairing a defective heart valve is disclosed. Themethod 200 is schematically illustrated in FIG. 11 a , in conjunctionwith FIGS. 1-10 . The order in which the steps are described should notbe construed as limiting, and it is conceivable that the order of thesteps may be varied depending on the particular procedure. The method200 comprises positioning 201 a first support ring 101 of anannuloplasty device 100 on a ventricular side of the heart valve, andpositioning 202 a second support ring 102 of the annuloplasty device onan atrial side of the heart valve. The first and second support ringsare thus arranged as a coil extending through a commissure 302, 302′ ofthe heart valve. The first and/or second support ring 101, 102,comprises a stent 105, 105 a, 105 b, 105 c arranged around at least aportion of the first and/or second support ring 101, 102. The stentcomprises retention units 104, 104′. The method 200 comprisespositioning 203 the stent 105 in abutment with valve tissue along theaforementioned portion of the first and/or second support ring 101, 102,so that the retention units 104, 104′, are engaged 204 into tissue ofthe heart valve. The method 200 provides for the advantageous benefitsas discussed above in relation to the annuloplasty device 100 and FIGS.1-10 . The method 200 allows for a facilitated anchoring of theannuloplasty device 100 at the heart valve, due to the robust andreliable fixation mechanism provided by stents 105, 105 a, 105 c, andthe retention units 104, 104′, fixed thereto.

A further method 200 is schematically illustrated in FIG. 11 b . Themethod 200 may comprise positioning 2031 an anterior stent 105 c on theatrial side along a first anterior portion 114 of the first support ring101, and positioning 2032 a first posterior stent 105 a on the atrialside along a first posterior bow 113 of the first support ring 101. Themethod 200 may further comprise positioning 2033 a second posteriorstent 105 b on the ventricular side along a second posterior bow 113′ ofthe second support ring 102.

The method 200 may further comprise engaging 2041 retention units 104 ofthe anterior stent 105 c into valve tissue on the atrial side, andengaging 2042 retention units 104, 104′, of the first and secondposterior stents 105 a, 105 b, into valve tissue on the respectiveatrial and ventricular side to anchor the annuloplasty device 100 at theheart valve. A secure fixation of the annuloplasty device at theopposite sides of the heart valve leaflets is thus provided, asdescribed further above with respect to FIGS. 1-10 .

The method 200 may comprise positioning the first and second supportrings 101, 102, on the respective atrial and ventricular sides of theheart valve by ejecting 2021 the first and second support rings from adelivery catheter (not shown), where the retention units 104, 104′, movefrom a retracted state (p₁) to an expanded state (p₂) as the first andsecond support rings 101, 102, are ejected from the delivery catheter.

The retention units 104, 104′, may be aligned essentially flush with anouter diameter (D) of the stent 105, 105 a, 105 b, 105 c, in theretracted state (p₁) when the first and second support rings 101, 102,moves along a lumen if the delivery catheter.

The present invention has been described above with reference tospecific embodiments. However, other embodiments than the abovedescribed are equally possible within the scope of the invention. Thedifferent features and steps of the invention may be combined in othercombinations than those described. The scope of the invention is onlylimited by the appended patent claims. More generally, those skilled inthe art will readily appreciate that all parameters, dimensions,materials, and configurations described herein are meant to be exemplaryand that the actual parameters, dimensions, materials, and/orconfigurations will depend upon the specific application or applicationsfor which the teachings of the present invention is/are used.

1. An annuloplasty device comprising first and second support ringshaving a coiled configuration in which the first and second supportrings are arranged as a coil around a central axis, wherein the firstand second support rings are configured to be arranged on opposite sidesof native heart valve leaflets of a heart valve, wherein a stent isarranged around at least a portion of the first and/or second supportring, and wherein the stent comprises retention units.
 2. Theannuloplasty device according to claim 1, wherein the retention unitsare formed from the material of the stent, whereby the retention unitsare integrated with the stent.
 3. The annuloplasty device according toclaim 1, wherein the retention units comprise a shape-memory material,wherein activation of the shape-memory material causes the retentionunits to transfer from a retracted state (p₁) to an expanded state (p₂).4. The annuloplasty device according to claim 1, wherein the retentionunits are resiliently moveable from a retracted state (p₁) to anexpanded state (p₂).
 5. The annuloplasty device according to claim 4,wherein the retention units are flexible to bend from the expanded state(p₂) to the retracted state (p₁).
 6. The annuloplasty device accordingto claim 5, wherein the retention units are aligned essentially flushwith an outer diameter (D) of the stent in the retracted state.
 7. Theannuloplasty device according to claim 1, wherein the stent comprises aplurality of support elements (108) forming a stent framework of closedcells (122), wherein a first support element (108 a) of the plurality ofsupport elements of a cell (122) is movable as a retention unit (104,104′) along a radial direction (R), perpendicular to a longitudinaldirection (L) of the stent.
 8. The annuloplasty device according toclaim 1, wherein the stent is radially contractible along a radialdirection (R), perpendicular to a longitudinal direction (L) of thestent, so that the stent exerts a force (F) on the first and/or secondsupport ring.
 9. The annuloplasty device according to claim 8, whereinthe stent comprises a shape-memory material, wherein activation of theshape-memory material causes the stent to contract to a reduceddiameter, along a radial direction (R), to apply said force on the firstand/or second support ring.
 10. The annuloplasty device according toclaim 1, wherein the stent comprises support elements configured to becontractible and expandable so that an outer diameter (D₁, D₂) of thestent is variable between an expanded diameter (D₁) and a contracteddiameter (D₂) while a predefined length (L₁) of the stent is essentiallymaintained.
 11. The annuloplasty device according to claim 10, whereinthe support elements comprise an elongated main frame extendingessentially along the longitudinal direction (L) of the stent, andwherein the elongated main frame defines the predefined length (L₁) ofthe stent, whereby the elongated main frame has an essentially fixedposition in the longitudinal direction (L) when the outer diameter ofthe stent varies between the expanded diameter (D₁) and the contracteddiameter (D₂).
 12. The annuloplasty device according to claim 1,comprising a cover arranged around at least a portion of the firstand/or second support ring, and wherein the stent is arranged around atleast a portion of the cover.
 13. The annuloplasty device according toclaim 12, wherein the stent exerts a force onto the cover so that thecover is pinched between the stent and the first and/or second supportring.
 14. The annuloplasty device according to claim 1, wherein: thefirst support ring comprises a first posterior bow and a first anteriorportion, the second support ring comprises a second posterior bow and asecond anterior portion, the first and second posterior bows are adaptedto conform to a posterior aspect of said heart valve, and the first andsecond anterior portions are adapted to conform to an anterior aspect ofsaid heart valve, the first anterior portion comprises an anteriorstent, the anterior stent comprising a plurality of retention units, andthe second anterior portion comprises a smooth surface free fromretention units.
 15. The annuloplasty device according to claim 14,wherein: the first posterior bow comprises a first posterior stentcomprising a first plurality of retention units, and the secondposterior bow comprises a second posterior stent comprising a secondplurality of retention units extending in a direction towards the firstplurality of retention units.
 16. The annuloplasty device according toclaim 1, wherein: the first support ring transitions to the secondsupport ring over a transition section; the transition section isadapted to be arranged at a commissure of the heart valve leaflets, thefirst and second support rings extend in respective first and secondcoil planes being essentially perpendicular to the central axis, and thetransition section bends at least partly along the central axis so thatthe first coil plane is separated a distance (d₁) from the second coilplane along the central axis at the transition region.
 17. A method ofrepairing a defective heart valve comprising; positioning a firstsupport ring of an annuloplasty device on a ventricular side of theheart valve, positioning a second support ring of the annuloplastydevice on an atrial side of the heart valve, whereby the first andsecond support rings are arranged as a coil extending through acommissure of the heart valve, the first and/or second support ringcomprising a stent arranged around at least a portion of the firstand/or second support ring, the stent comprising retention units, andpositioning the stent in abutment with valve tissue along said portionso that the retention units are engaged into tissue of the heart valve.18. The method according to claim 17, further comprising positioning ananterior stent on the atrial side along a first anterior portion of thefirst support ring, positioning a first posterior stent on the atrialside along a first posterior bow of the first support ring, andpositioning a second posterior stent on the ventricular side along asecond posterior bow of the second support ring.
 19. The methodaccording to claim 18, further comprising engaging retention units ofthe anterior stent into valve tissue on the atrial side, and engagingretention units of the first and second posterior stents into valvetissue on the respective atrial and ventricular side to anchor theannuloplasty device at the heart valve.
 20. The method according toclaim 17, further comprising positioning the first and second supportrings on the respective atrial and ventricular sides of the heart valveby ejecting the first and second support rings from a delivery catheter,whereby the retention units move from a retracted state (p₁) to anexpanded state (p₂) as the first and second support rings are ejectedfrom the delivery catheter.
 21. The method according to claim 20,wherein the retention units are aligned essentially flush with an outerdiameter (D) of the stent in the retracted state when the first andsecond support rings moves along the delivery catheter.